Chebyshev linkage application.　Piston movement application.[br]Bi-pedal walking apparatus.[br][i]Catch[/i] the [b]Red bullet ● B[/b], then [i]Please rotate it.[/i][br][br]Chebyshev parts/ leg = 4 bars (each length 4, 5, 5, 2)[br]Crank parts/ leg = 4 bars (each length AR [=rr], RD [=rr], CD [= long], EF [=2.5])[br][ Point E is on CD long bar, where ED = 2 ] ( [b]Remark :[/b] ED (or E'D) // B''[sub]1[/sub]G [= bottom of the foot])[br][br][b]As a matter of fact, purple method doesn't need long arm. This is great. [br]Please check it out.[/b] ( i.e. Do move ▲ C to the right direction. ex. x(C) ≒ -0.8 is OK. )

[b]Perhaps, This is very elegant solution in the world.[/b][br][br][br]The hinge elements AR and RD are shrunk in  y < 0 area. [br](---- This is an important trick.)[br][br]The direction of Crank rotation  is the same direction of forward movement. This is honest/ natural.[br][br]--- Like a "Row, Row, Row Your Boat" or Crawl swimming arm movement.[br][br][b]■ Simple structure for implementation in related Axis bar:　Simple chassis/ body structure.[/b][br]∠DB''[sub]2[/sub]B''[sub]1[/sub] ≦ 180°,　∠DB'''G ≦ 180°,[br]So, [br]point B''' and segment B''2B''[sub]1[/sub] doesn't conflict.[br]point B''[sub]2[/sub] and segment B'''G doesn't conflict.[br]So, 3D structure is very simple. [br] --- i.e. The cross 2 bars are in the same side of chassis. (Between 2 cross bars, there is no chassis. )[br][br][b]Tip:[/b] chassis is simpler than orthodox Chebyshev bi-pedal.[br]cf. [url=https://www.geogebra.org/m/aU52jYUG]Chebyshev_walker2[/url][br][br][b]■ Purple color structure has good property except more 2 bars.[/b][br]Foot trace curve is near the symmetry. [br]Bottom of the foot is always exact horizontal.[br][br][b]■ Compare other known method[/b][br] [br]cf. [url=http://www.sv-jme.eu/data/upload/2011/12/03_2010_210_Meneses_04.pdf]Kinematics and Dynamics of the Quasi-Passive Biped "PASIBOT”[/url] (Spain)[br]---- No originality, I think so.[br]---- This is a point symmetry application, so, foot trace shape is identical with Chebyshev curve shape.[br] ( big height stroke ratio tuning cannot be done. [ height/ width ratio is constant. this is bad. ] )[br][br]cf. [url=https://www.geogebra.org/m/Mes3Rb8P]The piston[/url] [b]R = L[/b] case, please.[br]---- My apparatus is a typical piston movement.[br]( i.e. crank clockwise 0° to 180° is mapping to clockwise 0° to 180°,[br]clockwise 180° to 360° is mapping to counterclockwise 0° to 180°. )[br][br][b]■ About precise number of bars.[br][/b]Crank AR ●-◇ is a part of a bent bar I''AR, so, precisely it's not different bar.[br]Bar DR ●-◇ is a part of a bent bar B''[sub]2[/sub]DR, so, precisely it's not different bar.[br][br]So, (4 + 4) bars/ leg is (4 + 2) bars/ leg is true, precisely.[br]corresponding to this, (4+6) is (4+4) is precisely.[br][br][b]■ In real world:[/b][br]In big gap barrier _____|‾‾‾‾‾‾ floor case, asymmetry is better than symmetry trace foot.[br]and it has more simple structure. [br][b]R ◇[/b] tuning mechanism is indispensable. variable hinge length. (Please check R on A' case. very high step. [br][b]----- It' easy to jump 10cm high gap.[/b] )[br][br]cf. [url=http://home.c00.itscom.net/t2oho4no/fukusitaiken/kurumaisu/kurumaisu.htm]Wheelchair operation[/url] cf2. [url=http://www.wikihow.com/Use-a--Wheelchair]How to Use a Wheelchair[/url]